git: c48cbd0254de - releng/13.0 - powerpc64: Fix boot on virtual-mode OF (PowerMac G5)
Brandon Bergren
bdragon at FreeBSD.org
Wed Feb 10 03:43:37 UTC 2021
The branch releng/13.0 has been updated by bdragon:
URL: https://cgit.FreeBSD.org/src/commit/?id=c48cbd0254dedd363ab569692ddf3395b6214412
commit c48cbd0254dedd363ab569692ddf3395b6214412
Author: Brandon Bergren <bdragon at FreeBSD.org>
AuthorDate: 2021-02-07 22:05:41 +0000
Commit: Brandon Bergren <bdragon at FreeBSD.org>
CommitDate: 2021-02-10 03:42:44 +0000
powerpc64: Fix boot on virtual-mode OF (PowerMac G5)
In 78599c32efed3247d165302a1fbe8d9203e38974, CFI endproc decoration was
added to locore64.S. However, it missed the subtle detail that
__restartkernel_virtual() falls through to __restartkernel(). This was
causing boot failure on PowerMac G5, as it tried to execute the
epilogue as code.
Fix this by branching to __restartkernel() instead of intentionally
running off the end of the function.
While here, add some additional notes on how the virtual mode restart
works.
Approved by: re (gjb)
(cherry picked from commit d26f2a50ff48dacd38ba358d658882d51f7bdbc4)
(cherry picked from commit 187492ef639fecde6c122838cfff0a75d8b94608)
---
sys/powerpc/aim/locore64.S | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/sys/powerpc/aim/locore64.S b/sys/powerpc/aim/locore64.S
index 0bc0619620d9..f0a183c4b331 100644
--- a/sys/powerpc/aim/locore64.S
+++ b/sys/powerpc/aim/locore64.S
@@ -255,6 +255,16 @@ ASENTRY_NOPROF(__restartkernel_virtual)
addi %r14, %r14, 1
cmpdi %r14, 16
blt 1b
+
+ /*
+ * Now that we are set up with a temporary direct map, we can
+ * continue with __restartkernel. Translation will be switched
+ * back on at the rfid, at which point we will be executing from
+ * the temporary direct map we just installed, until the kernel
+ * takes over responsibility for the MMU.
+ */
+ bl __restartkernel
+ nop
ASEND(__restartkernel_virtual)
ASENTRY_NOPROF(__restartkernel)
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